Currently, in various fields such as nuclear physics and radiotherapy use is made of semiconductor elements for detecting radiation, formed from group II-VI semiconductors, typically CdTe-based compound semiconductors. In recent years it has been proposed to obtain images using these semiconductor elements, and in order to achieve this it is deemed necessary for an electrode layer formed on the surface of the element to be divided electrically to form a pixelated semiconductor element which has multiple pixels (picture elements). One technique for forming such a pixelated semiconductor element is disclosed in Japanese Patent Kokai 2004-128238.
Japanese Patent Kokai 2004-128238 discloses a method in which an electrode layer on a substrate surface is cut mechanically by half-cut dicing or the like, the electrode being divided by means of the cut grooves. More specifically, a semiconductor wafer is subjected to half-cutting by dicing using a dicing blade (dicing saw), forming dividing grooves having a rectangular cross section and a target width of 50 to 200 μm, as shown in FIG. 2 of Japanese Patent Kokai 2004-128238.
A dark current (leakage current) is a factor which determines the performance of a semiconductor element for detecting radiation. To elaborate, it is known that an element having a small dark current has a high performance, and it is thus essential to reduce the dark current in order to improve the performance of future semiconductor elements. On the other hand, with a construction having dividing grooves formed using the abovementioned known mechanical cutting method it is difficult to suppress the dark current to a level that can meet existing or future demands, and it is problematic for semiconductor elements having satisfactory performance to be manufactured with a good yield.